There used to be an chief appraiser in Delaware Co., OK named George. George was working on a sketch one day and was using LandChec, an old DOS survey module. He had worked all day on it. It was a nightmare. I always dreaded getting an assignment for such. I got one. ~6800 SF if i recall, 3 stories+ basement, the lower was a basement, you could measure only part of 2 sides of the basement, the first floor was above ground on part and the upper levels. The basement was smaller than the footprint of the upper level. A foot bridge went into the house at Fl 1. The upper floors were irregular boxes stacked at 45 degree angles and were slightly larger. You would have needed a 60' ladder, make that 2 ladders to meaure.
We guessed at it. We went to the assessors sketch and it was close. Talked to George. They guessed at it too.
The accuracy of the measurement may be a badge of honor to appraisers, and I certainly don't want to discourage anyone from measuring every time...that's why we have not done driveby appraisals since 1996. How can you know? Then again, if we are depending upon MLS and/or Public records data for SF of the comps, how accurate are our adjustments? Not any better than the accuracy of the realtor/assessor. Except we have measured it ourselves, we almost never have any SF source except the owner, the public records, the bank (usually very reluctant to give you a copy of the appraisal) or MLS for comps..and 90% of the MLS estimates come from the assessors sheet..which is good. At least they put down the right figure and not the gross SF with garage included. 50% of owners give you SF that includes the garage.
Finished a Motel. No measurement. We had a survey in hand and engineering drawings with the dimensions surveyed in. Far better measure than we could have done because we don't have a 300' tape. A wheel is not perfect on rough ground like an asphalt parking lot that is breaking up. And it documents well.
Fit the work to the project. An old barn in a field, a small shed, what value are they? probably none. Your personal measurement is meaningless. If the owner tells me his pool is 20' x 40' and i know its only 18' x 36' kidney shaped, does it matter? Not really. He counts the apron around the edge. It matters even less if its 18.2 x 35.9'...that implies an accuracy I doubt we are capable of. one-tenth of foot measurements for farm buildings, again, is much overkill and misleading to a point. The owner contracts for a 43' x 500' poultry barn, the integrator requires it, the builder bids on it, and the owner is paid per SF based upon it...my 43.2' x 501.1' measurement is meaningless.
Some assessor records are better than others. SW Missouri...sux putty balls. NE Oklahoma...pretty good but sometimes dated and misses updates. Arkansas...very good most parts. New construction in some backwoods counties don't show up for years though...ditto for remodels.
Due diligence in residential appraising suggests that physical measurement by the appraiser is appropriate. But that is not the case for a lot of properties.
